Amazon Instant Video is a digital video streaming and download service that lets users rent, buy or subscribe to a range of videos. Prime Instant Video is Amazon’s video subscription service which, at the time of writing, makes more than 18,000 movies and TV shows available to stream. It’s free to those who subscribe to its 2-day shipping service Amazon Prime, charged at an annual rate of $79.

Both Fringe and The West Wing are to be made available exclusively on Prime Instant Video for the summer. “Since launching Prime Instant Video, we’ve continued to expand both the quantity and quality of video content for our Prime members,” said Brad Beale, director of digital video content acquisition for Amazon. “Bringing Fringe and The West Wing – two shows with a devoted fan base – to Prime Instant Video first, is another way for us to add value for Prime members and to continue to give customers content they love.”

Amazon launched its Prime Instant video service last February, a service which is currently only available in the US. Viewers can watch content on the Kindle Fire, Xbox 360, PlayStation 3 and more. You can see a full list of devices here.

Amazon is really beginning to ramp up its media offering, having inked a deal with Paramount earlier this year too. Throw into the equation its Amazon Studios division, which is developing fresh content based on user submissions (such as Zombies vs. Gladiators), the Internet giant is beginning to cement itself in the VoD space and could become a genuine rival to services such as Netflix. Indeed, it already is in the UK, with LoveFilm, which it acquired last year.